Kidneys and Suprarenal Glands Flashcards
What are the functions of the kidney?
- Production of urine
2. Endocrine functions
What are the endocrine functions of the kidney?
- Renin for angiotensin system
2. Erythropoietin –> directs hemopoietic stems into proerythroblasts
What are the 2 parts of the suprarenal glands?
- Cortex
2. Medulla
Describe the cortex of the suprarenal gland and its function:
Paler, outer region that is essential to life (Addison’s dx)
- mineralocorticoids for H2) and electrolyte balance
- glucocorticoids for carb metabolism
- sex hormones
What is the function of the medulla of the suprarenal gland?
- Epinephrine for HR
- Norepinephrine for BP via vasoconstriction
- Fight or flight response
Is the kidney peritoneal or retroperitoneal?
Retroperitoneal
What does the posterior surface of the kidney contact?
- Superiorly: diaphragm
- Inferiorly: psoas major, quadratus lumborum, and transversus abdominis
The kidneys extend from which vertebral levels?
T11 to L3
The superior pole of the R kidney is at the level of the:
12th rib
The superior pole of the L kidney is at the level of the:
11th rib (L kidney is a little higher up, usually)
What is the hilum of the kidney?
Vertical, medial fissure through which vessels, nerves, and the renal pelvis enter or exit the kidney. Lateral to the hilum, these structures pass thru a fat-filled cavity - renal sinus
What is the renal parenchyma?
Renal cortex and renal medulla
What is the renal cortex made up of?
Granular appearing tissue located beneath the fibrous capsule. Renal columns is continuous with the renal cortex; they extend inward between the renal pyramids of the renal medulla
What is the renal medulla made up of?
18 cone-shaped renal pyramids whose bases are outwardly directed. The apex of the renal pyramid is the renal papilla.
The renal papilla are capped by:
Minor calyx, which extend into the renal sinus
How does urine get to the ureter?
Within the renal sinus, a funnel-shaped renal pelvis receives input from 2 or 3 major calyces. Each major calyces receives input from several minor calyces, which cap individual renal papillae. Exiting the kidney medially, the renal pelvis narrows near the inferior pole of the kidney and transitions into the ureter
Is the ureter peritoneal or retroperitoneal?
Retroperitoneal
How does the ureter descend? (over what structures)
Descends on the ANTERIOR surface of the psoas major muscle and passes POSTERIOR to the gonadal vessels, courses ANTERIOR to the bifurcation of the common iliac artery and then makes a sharp bend over the pelvic brim and courses to the bladder in the floor of the pelvis
What is the renal fascia?
Membranous CT layer surrounding the perirenal fat. It merges medially with the adventitia or the renal vessels, superiorly (above the hilum) the fascial layers fuse with each other, and inferior to the hilum, the renal fascia is continuous with the CT surrounding the ureter
The renal fascia creates this space:
Perinephric space (R and L) which is occupied mostly by perirenal fat
Do the R and L perinephric spaces communicate?
NO, they do not communicate across the midline, however the spread of infection or hemorrhaging from structures contained in this space (kidney, ureter, renal vessels, and suprarenal gland) allow an unobstructre path (contained by the perinephric space) for its spread from the kidney/suprarenal glands, all the way down into the pelvis
What is in between the kidneys and the suprarenal glands?
A thin fascial septum (from the renal fascia) separates the suprarenal gland from the superior pole of the kidney
What are the contents of the perinephric space?
- R or L kidney
- R or L ureter
- Suprarenal gland
- Distal renal, suprarenal, and ureteric vessels
- perirenal fat
What is perirenal fat?
Adipose tissue between the fibrous capsule of the kidney and the renal fascia surrounding the kidney/ureter. This is continuous with the fat within the renal sinus
What is pararenal fat?
Adipose tissue located external to the renal fascia. The pararenal fat invests the kidney and suprarenal glands
Anteriorly, what is the pararenal fat covered by?
Parietal peritoneum
Posteriorly, what is the pararenal fat covered by?
Transversalis fascia
What structures are related to the ANTERIOR surface of the R kidney?
- Suprarenal gland
- Liver
- Duodenum
- Hepatic flexure of colon
- Small intestine
What structures are related to the POSTERIOR surface of the R kidney?
- 12 rib and diaphragm
- Psoas major
- Quadratus lumborum
- Aponeurosis of transversus abdominis
What structures are related to the ANTERIOR surface of the L kidney?
- Stomach
- Spleen
- Pancreas (tail)
- Splenic flexure of colon
- Suprarenal gland
- Jejunum
What structures are related to the POSTERIOR surface of the L kidney?
- 11th and 12th rib
- Diaphragm
- Psoas major
- Quadratus lumborum
- Aponeurosis of transversus abdominis
What vertebral level is the IVC with hepatic veins coming off?
T8
What vertebral level does the esophagus enter the abdomen?
T10
The celiac trunk is at:
T12
What vertebral levels is the hepatic felxure of the colon at?
L2
The first part of the duodenum is at:
L1 (and the hilum of kidney)
The transverse part of the duodenum is at:
L3
What is the blood supply to the kidneys?
R and L renal arteries
Describe the course of the R&L Renal arteriers:
Course laterally from the aorta and POSTERIOR to the renal veins. Before entering the hilum, the renal artery divides into anterior and posterior rami which pass anterior and posterior to the renal pelvis –> divide into segmental branches
What is special about the segmental branches of the R&L renal arteries?
They do not anastomose
What is a distinguishing characteristic of the R renal artery?
It is LONGER than the left and courses POSTERIOR to the inferior vena cava
Where do the renal veins drain?
Into the inferior vena cava. At the hilum, tributaries which form the renal vein, emerge anterior and posterior to the renal pelvis
Describe the course of the L renal vein:
It courses POSTERIOR to the pancreas and ANTERIOR to the abdominal aorta, just INFERIOR to the origin of the superior mesenteric artery
What are tributaries of the L renal vein?
L suprarenal vein and L gonadal vein
Describe the course of the R renal vein:
Courses POSTERIOR to the descending part of the duodenum and the head of the pancreas
Where does the R renal vein drain?
Directly into the IVC
What are the tributaries of the R renal vein?
There aren’t any - the R suprarenal and R gonadal veins drain directly into the IVC
What drains into the L suprarenal vein?
L inferior phrenic vein
What are the functional lobes of the kidney defined by?
Segmental arteries of the kidney
What do the segmental arteries come off of?
There are 5 that come off each renal artery. Each segmental artery supplies a separate lobe of the kidney. Since there are no anastomotic connections made between the segmental arteries, there is no arterial communication between the lobes they define.
What happens if a segmental artery is obstructed?
It will result in complete loss of the lobe it supplied
Where do lymphatics from the kidneys and suprarenal glands drain?
Into lumbar nodes
Where do the lumbar nodes go?
Flow via the lumbar trunks into the CISTERNA CHILI
What are ureters?
Paired smooth muscular tubes that begin at the narrowing of the R and L renal pelvis and terminates at the bladder, They are both crossed anteriorly by the gonadal artery and vein, and they cross anteriorly to the common iliac and the psoas major
Additionally, the L ureter is crosses anteriorly by the:
Inferior mesenteric artery and vein
Describe the ureteric blood supply:
It is derived from multiple sources because anastomotic connections with neighboring branches are often incomplete
Arterial supply to the ureters comes from (5) branches:
- Renal arteries - supplies the first (proximal) 5-7cm of the ureter
- Abdominal aorta
- Gonadal arteries
- Common and internal iliac branches
- Branches from the superior vesical (male and female) and inferior vesical (mle only)
Describe the vasomotor/sympathetic input to the kidneys:
An aorticorenal ganglion (paired) located on the renal artery receives PREGANGLIONIC sympathetic fibers from the lesser and least splanchnic nerces; POSTGANGLIONIC sympathetic fibers from the aorticorenal ganglion are distributed to the renal a (and its branches)
What is the function of the vasomotor/sympathetic input to the kidney?
Decrease blood flow/Na+ secretion and increase renin secretion
What do sensory afferents travel with?
With the lesser and least splanchnic nerves and mediate visceral pain, which is referred to the costal angle of the back
Describe the parasympathetic innervation to kidney/suprarenal glands:
Not well understood
Describe the innervation to the ureter:
PREganglionic sympathetics from the lesser and least splanchnics, as well as from lumbar and sacral splanchnics synapse in sympathetic ganglion assoc with the aorta –> POSTgang in turn serve to increase ureteric peristalsis when stimulated
Sensory afferents travel back via the:
Lesser and least thoracic and lumbar splanchnics.
Pain resulting from an infection of kidney stone is referred to the dermatomes:
T10-L2, along the posterior costal margin
Stones caught in the distal portion of the ureter are perceived to the suprapubic region, genitals, medial thigh and leg, referred to dermatomes:
L1-L2
Are the suprarenal glands (SRG) peritoneal or retroperitoneal?
Retroperitoneal
What space are the SRGs located in?
Perinephric space (invested by perirenal fat and then by renal fascia) and are separated by a thin fascial layer from the kidney
What is the R SRG related to?
IVC and the R lobe of the liver POSTERIORLY
What is the L SRG related to?
Aorta, LATERALLY
Why is the medulla more darkly stained?
Due to melanin accumulation in the secretory cells (byproduct of catecholamine production). These cells are responsible for the release of E and NE and are signaled directly by PREganglionic sympathetic fibers that reach the SRG from the GREATER splanchnic n
Describe blood supply to the SRGs via the suprarenal arteries:
There are 3 arterial supplies going to each SRG
- Superior suprarenal arteries
- Middle suprarenal arteries
- Inferior suprarenal arteries
Where does the superior suprarenal artery come from?
(6-10), branch from the INFERIOR PHRENIC A and enters the SRG along the superior medial border
Where does the middle suprarenal artery arise from?
The ABDOMINAL AORTA above the renal artery and enters the SRG medially (the R usually passes posterior to the IVC)
Where does the inferior suprarenal artery arise from?
The RENAL A, and enters the SRG at its inferior border
The left suprarenal vein drains into:
The L renal vein (each suprarenal gland has 1 suprarenal v)
The right suprarenal vein drains into:
The IVC directly
What is the innervation of the cortex of the SRG?
POSTganglionic sympathetics from the CELIAC ganglion that are driven by the PREganglionic fibers from the greater splanchnic n. These fibers act directly on blood vessels
What is the innervation of the medulla of the SRG?
It receives direct input from PREganglionic sympathetic fibers arising from the greater splanchnic n. These fibers synapse directly on CHROMAFFIN CELLS (modified postganglionic sympathetic neurons) and facilitate the release of E and NE into the blood stream
Describe the sensory afferents in SRG:
They are absent
Parasympathetic innervation in the SRG is:
Not understood
What is a horshoe kidney?
As the R and L kidneys ascend out of the pelvis, they can fuse at midline and be held up by the INFERIOR mesenteric artery - forming a single horseshoe kidney
What are accessory renal arteries?
In 20% of people, they do NOT pass thru the hilum, but enter the kidney on the extrahilar surface
What is Addison’s disease?
1 in 100,000 people. Most cases are caused by the gradual destruction of the adrenal cortex by the body’s own immune system –> both glucocorticoid (cortisol) and mineralcorticoid (aldosterone) hormones are lacking
What is the importance of cortisol?
Maintain BP and CV function, balance the effects of insulin in breaking down sugar for energy, regulate metabolism of proteins, carbs, and fats.
What is the importance of aldosterone?
Loss of func compromises the maintenance of BP, as well as maintaining normal water and salt balance by the kidneys
Kidney transplants:
Occur in plevis (tap into the internal iliac vessels). This is primarily due to the blood supply to the ureter (renal a supplies proximal 5-7 cm) so due to poor anastomotic connections, dissected ureters with segments extending beyond 7 cm usually do not survive a transplant and undergo ischemia/necrosis